Warning-signal system



Jul; 28, 1925. r Y

' R. R. EARLE WARNING S IGNAL I SYSTEM Filed Aug. 28, i922 Z SheetS-Shee't 1 v gmentu kelp/L 1?. Earle, v

Jul 28, 1925; R. R. EARLE 1 WARNING SIGNAL SYSTEM Filed Aug. 28, 1922 2Sheets-Sheet 2 z wbzz'arze,

Patented July 28, 1925.

RALPH R. EARLE, SAN FRANCISCO, CALIFORNIA.

WARNING-SIGNAL sxsrnm.

Application filed August 28, 1922. Serial No. 584,688.

To all whom it may concern:

Be 'it known that I, RALPH citizen of the United States, residing at SanFrancisco, in the county of San Francisco and State of. California, haveinvented new' and'useful Improvements in WarningSignal Systems, of whichthe following is a specification.

This invention relates to warning or alarm signals to be used inconnection with a machine or piece of apparatus to indicate to theoperator when certain predetermined limits have been passed. Such limitsmay be of pressure, as in a boiler, or of speed, as in an engine, motorvehicle, or other moving apparatus. While I do not intend to limit theapplication of my invention to any particular machine or use, it is welladapted for use on automobiles, to warn the driver when the speed of hiscar has exceeded a predetermined maximum and when its speed has beenreduced below a predetermined minimum, and I will describe the inventionas applied to such use. The warning signals may be audible or visibledevices, but I prefer to use visible ones, in the form of two electriclamps of diflerent colors, both of which are-in circuit as long as thespeed lies between the desired maximum and mini mum and one or the otherofwhich is extinguished whenever one or the other of said limits isexceeded.

It is a well known fact that, when operating a motor car in traflic orat high speed in the country, the drivers eyes a're focused at aconsiderable distance in advance of the car. If he wishes to know whatspeed he is making, he must, change the focus of his eyes, s'hift hisangle of vision and read the speedometer at very close range.

eyes and nerves, as to take his eyesfrom-the road ahead, for even a,second or two, may spell disaster. It is also wellknown that the humaneye sees in a general 'way objects at. which it is not directly lookingand that the mind records impressions subconsciously orwithout anyconscious effort of the brain.

This is illustrated by the fact that ones attention will at once beattracted by the extinction of one light only in a room' illuminated byseveral lights, although one was not previouslyconscious of thefa'ct'that several lights were burning.

R. EARLE, a

All this requires time and is a strain on the drivers' nated as long asI make use of these facts in the construction and operation of thewarning signal system whichconstitutes my present lnvention, by placingthe two lights of different colors in the line of vision of the operatorso that, in the normal operation of the machine, he will not beconscious of-.. them or have his eyes focused on them but his attentionwill inevitably be called to the fact that I one of them has gone out,so that, without changing the focus-of his eyes or his angle of vision,he will know that he has exceeded one of'the predetermined speed limits.It will be obvious that this principle of warning signal system isequally applicable to indicate undesirable ,variatlons in the pressureof a steam boiler, in the level of a liquid,

the number'of revolutions of a shaft, in the f course of direction ofavessel, etc., said principle being the maintenance of a continuousindication that conditions are normal as long.

as such .is the case and the changing ,of sai indication, to which theeye or earhas become accustomed, whenever conditions become abnormal. Inthis articular, I believe that my system difl'ers f?- In its applicationto an automobile, I prefer to locate the visual signal devices on' thein. other uses of the system, they will be placed in such a positionthat the operator or erson in charge will have his attentlon om allprior ones.

'lower part of the wind-shield, just beneath the normal line of visionof the driver while,.

cal ed when a change in said devices takes place.

As applied to comprises two a which can be set at the desired maximumand minimum, and a movable contact mem- (sipeed control, the inventionher the angular position of which is determined at all times by thespeed of the car or machine, preferably by means of a centrlfugalgovernor, the two lamps, one showing,

for example, a red light and the other a green light, and suitableelectric connections whereby both lights are maintained illumitge speeddoes not exceed the maximum or mum speeds chosen. a

In the accompanying drawing, v

Fig. 1 is a front. elevation of the dash instrument board of anautomobile or motor iminish below the mini ustable contact members,

boat equipped with my warning signal system.

Fig. 2 is a .front elevation, on a larger scale, of the casingcontaining the mechanism 4 7 members in side elevation.

' mounted, as illustrated in Fig. 1', on the in-. strument board belowthe'wind-shield of an.

The signal lamps, one showing a red light and the other a green light,are shown -at,10 the switch controlling thecar lights an contromechanism of my signal system at 12, an the usual speedometer at 13, all

automobile, but it will be obvious that the lamgs 10 may be locatedelsewhere if de- Within the casing 12 is a small centrifugal ballgovernor l i, the shaft 15 of which is driven,- as by a flexible shaft16, from any moving part of the vehicle, so that the speed of rotationof said shafts is always roportional to the speed of, the vehicle. egovernor ball arms are connected to a disc 17,

v slidable on the' shaft 15 and acting upon the crank-pin 18 of an arm19 carried by the shaft 20, jonrnalled centrally in the casing 12 andcarrying on its front end the indicating hand 21, which plays over thecircular scale 22, graduated to miles per hour. A coil spring 23 tendsto turn the shaft 20 backwardly and to'keep the crank pin 18 in con tactwith'thedisc 17. Thefront of the. casing isclosed by a lass 24, on-whichthe scale 22 maybe insclii d. Loosely mounted on the shaft 20 are two.arms '25, projecting through slots in the casing and extending 1 1forwardly downwardly to form indicator pointers 26, cooperating with thescale 22, while u" standing portions 27 form finger pieces an arepreferably colored to correspond to the lamps. These arms are adjustableover the scale and are clamped in adjusted position by set-screws 28, orthe hke. The arms 25, within the casing, carry respectively contacts 35and 36, with which they engage at certain timesthe contacts 33 an 34,carried by the arms 29 and '30, re-

spectively, whicharms, are also. loosely mounted on the shaft 20 and arepressed towards the contacts 35 and 36 by their respective springs 31'and 32. Contacts 33 and 34 are electrically connected by wires 37 and 38to terminals 40, mounted on but insulated from the casing 12 and fromwhich wires {11 and 42 to the lamps 10 and thence the circuit isfcompleted back-to the casing at terminal fiythrough the battery 45, bywire 43. It will be understood that the easmgv constitutes a groundconnection and that the arms and their contacts 35 and 36 areconductively-connected with said ground.

tively, and the arms .25 are set at those atrest or just starting,.igmtion at1'11, the casing containingtthehour. At that time, thegovernor balls have contact 33' being held away from contact 35 Fast onthe shaft 20 is the actuating arm48 which, in .the osition shown in Fig.3, is in engagement with a hook member 49 carried by the contact arm 29.Arm has a lateral extension 50,. y which it can engage arm 48, as willnow be explained.

Let us assume that the speed limitswhich are chosen to define the,normalrange of speeds, are 25 and miles per hour, respeclimits, as illustratedin 2. The car being t e circuit through the green lamp is closed throughcontacts 34- and 36, while that of the red lamp is open,

by 'actuating'arm 48 which is in engagement with the book 49 of arm 29.This condition continues until the speed has attained the minimum normalspeed of 25 miles per risen sufiiciently to turn the shaft 20 and, withit, the actuating arm 4:8 in clockwisedi -rection until the arm 29,under the influence -of'its spring 31, has been allowed to turn alsoandbring its contact 33 into engagement with the, contact 35 on the arm25, whereb the circuit through the :red lam is close both lamps beingnow illuminate and so remaining as long as the speed continuesibe tween25 and 35 miles per hour.- As the speed increases above 25 miles perhour, the

actuating .armj48 continues to turn to the right, until finally it comesinto contact with the extension 50 of contact arm 30, whereby contact 34of the latter is'separated from contact 36 of the arm 25 correspondingto the green lamp. Consequentl the. sen lamp is extinguished, leavin te. red am burning alone. As the spec is diminishe the reverse sequenceof oerations, of course,

takes place, the result bemg that, as lon as v the car'is being riven atnormal spee' in the case assumed, between 25 and 35 miles 'per hour, thedrivers attention is not specifically attractcdby the signal lampsbecause both of them are burning. But, if he exceeds the speed selectedas the maximum permissible, his attention is attracted to that fact bythe extinction of the green light and on the other hand, if hereduces'the speed below the minimum of 25 miles, his attention is drawnto that fact by the extinction of the 1 red be ma light. While changesmail obviously e in the selection of the '11d of Sig nal, the variationswhich they undergo when the limits chosen are surpassed, as welloas inthe limits to be chosen, it will be understood that the essentialfeature of my im proved warning signal system lies inthe maintenance ofcertain conditions asJong 'as operating conditions are ,norinal,'.orbetween the selected limits, and in the changing of those conditionswhen, either limit is s assed, Eso'-" that the o ratoishttehtibn wi beattracted subconsclolisl "*sa'ws' ak 1 Y: P a I 1. A warning signalsystem of the kind' described, comprising two adjustable limit contactmembers, two electric signal devices in circuit with said members, twomovable contact members adapted to engage said adjustable contactmembers, and an actuating member responsive to variations in speedconditions and constructed and arranged to control said movable contactmembers, whereby said signal devices are maintained operative as long asconditions are normal but one or the other of them will be renderedinoperative whenever either the maximum limit or the minimum limit ofthe variable conditions is surpassed.

operator of a moving vehicle, comprising two electric lamps of differentcolors located in his line of vision, a governor driven by the vehicle,a rotatable arm controlled by said governor, two movable contact membersadapted to be successively engaged by said arm, two adjustable fixedcontact members, and yielding means adapted to hold said pairs ofcontact members in engagement,

whereby both said lamps are maintained illuminated as long as theoperating limits determined by the position of said adjustable contactmembers are not surpassed but one or the'other of said lamps will beextinguished when either of said limits is surpassed. v

In testimony whereof l have hereunto set my hand.

RALPH lit. EARLEG

